This invention relates to a trolley base intended for use with a detachable trolley top or pallet for transporting loads. Particularly it relates to a trolley base which can be collapsed or folded for transportation when not loaded.
Trolley bases are known from U.K. Patent Applications Nos. 2123761 and 8531922 which have wheel means on which they can be pushed over the ground in an erected working condition and which are movable by a double folding action between that erected working condition and a folded condition. They are intended particularly, but not exclusively, for moving a heavy object from one support surface into a vehicle for transport to a further situation. With such a trolley the load is wheeled on the trolley to adjacent the back of a car, the load supporting surface or trolley top is moved off the trolley base onto the floor of a car and the base collapsed and also placed in the car; at the other end the base is again erected and the trolley top with the load on it is slid or rolled back on to the base for further transportation on the trolley.
Both these trolley bases have an adjustable height so that the top of the trolley base can be aligned with the support surfaces at the back of the car. However, it is not easy to adjust the height once the load is on the trolley base and if it is required to remove the object to yet another support surface at a different height, problems arise.
One height adjustable trolley base with an attached lifting means is known from U.K. Patent Specification No: 2157258. However, we have found that this type of lifting means is entirely unsatisfactory where a considerable load is on the trolley since it contains no support and guide means and causes bending and twisting of the trolley base.